Process and device for chopping a body of solid explosives, especially composite rocket fuels

ABSTRACT

A method for chopping a body consisting of explosives is described, by which a high-pressure water jet emerging from a nozzle is directed against the body of solid explosive and in which the nozzle and the body carry out a movement relative to each other during the chopping. Preferred fields of use are composite rocket fuels. There is also described a device for carrying out the process, in which the body of composite rocket fuel to be decomposed or divided into portions is secured on a chopping bench, and a nozzle fastened to a nozzle holder for the high-pressure water jet as well as at least one means for producing a relative movement serving as chopping advance movement between the nozzle and the body of composite rocket fuel are provided.

BACKGROUND OF THE INVENTION

The present invention relates to a process and device for chopping abody of solid explosives.

Solid explosives are used in relatively large quantities or numbers insolid rockets and engines of all kinds, such as, for example,ground-to-air, ground-to-ground and air-to-air rockets. Such rockets andengines are contained in large numbers in warehouses for storage and areto be fed for decomposing, recycling or destruction. For this, safe,ecologically clean and efficient technologies are required. Thecomposite fuels used for solid rockets contain a high proportion of 60%to 80% of an oxidizing agent and of aluminum in powdered form within arange of 5 to 10%. As oxidizing agent, ammonium perchlorate, potassiumperchlorate or ammonium nitrate is generally used. In this connection,it is to be noted that at 240° C. ammonium perchlorate (NH₄ ClO₄) forinstance gives off chlorine as a strong respiratory poison and oxygen tosupport combustion. In addition to this, there is the problem in thecase of solid fuels that they are capable of becoming statically chargedwhen worked on. The static charges can lead to voltages of up to 1000 V.The electrical discharges, which necessarily take place in thisconnection can, to be sure, not ignite the solid fuel in view of theirshort life, but they can, however, ignite the dust or powder produced inthe event of dry working, such as sawing, grinding, etc., which dust orpowder in its turn can lead to the igniting of the solid fuel.Furthermore, solid rocket fuels have high sensitivity to impact andfriction.

For the disposal of ammunition and solid fuels of rockets of smallrange, use has been made up to now of "open air" burning for a limitedtime of small amounts of fuel, pursuant to exceptions granted by thecompetent authorities. Due to the relatively large number of solidrockets and engines as well as the large weight of monolithically castbodies of solid fuel, "open air" burning is therefore out of thequestion also from an ecological standpoint. Therefore, a treatment ofthe solid fuels, in which reactions which represent a danger to man andenvironment can be excluded, must be assured.

Burning the solid rocket fuel without previously dividing it into smallportions is not possible, particularly in the case of rocket engines oflong-range rockets, due to the high mass of burnable substance in thetotal mass of the rocket.

At the present time, no technologies for the decomposing or dividinginto portions of composite rocket fuels are known. This may be due,inter alia, to the fact that the decomposing/destruction of rockets ortheir engines has not been necessary in the recent past.

The object of the present invention therefore is to provide a processfor the chopping of solid explosives and a device for carrying out theprocess, with which larger monolithic bodies of solid fuels,particularly composite rocket fuels, can be decomposed or divided intosmaller parts.

SUMMARY OF THE INVENTION

This objective is accomplished by a process and a device for carryingout the process for the chopping of a body of solid explosives, inparticular composite rocket fuels, a high-pressure in which water jetemerging from a nozzle is directed against the body of solid explosive,the nozzle and the body of solid explosive carrying out, at the sametime, a movement relative to each other during the chopping. The use ofa high-pressure water jet as chopping tool effectively avoids thedangerous thermal effects, which take place upon other mechanicalmethods of separation, in the manner, for instance, that the thermalenergy produced upon the chopping is led away by the water, which actsas coolant. Another important advantage is that the process can becarried out under conditions of ambient pressure and at the same timeundesired ignition of the solid fuel can be prevented.

In a preferred embodiment, the process for chopping bodies consisting ofsolid explosives is applied to a body of composite rocket fuel. In orderto increase the speed upon the chopping of the body of solid compositerocket fuel, abrasive particles are added to the high-pressure waterjet.

The chopping advance movement can be realized by fixing the position ofthe nozzle and moving the body of composite rocket fuel, by moving thenozzle and fixing the body, or by moving both the body and the nozzle.

In another preferred embodiment, a chopping advance movement takes placearound at least two axes in order to be able to obtain curved orinclined chopped surfaces. Depending on the nature of the compositerocket fuel, the high-pressure water jet emerges from the nozzle with apressure within the range of 30 to 120 MPa.

If the composite rocket fuel is contained within a casing, then, in afurther embodiment, this can be effected by high-pressure water-jetchopping within the casing between the inner surface of the casing andthe outer surface of the composite rocket fuel, so as to scoop the bodyof composite rocket fuel out of the casing. The scooping is possiblewithout cutting through the body of fuel and casing since a binder ispresent between the body and the casing.

Since the dividing of composite rocket fuels into portions falls withinthe technologies of potential danger, it is possible, in anotherpreferred embodiment, for the chopping advance movements of nozzleand/or body of composite rocket fuel as well as selected parameters ofthe high-pressure water jet, such as pressure of emergence, diameter ofthe jet, focusing of the jet, proportion of abrasive particles in thehigh-pressure water jet, etc. to be remote-controlled.

An inventive device for the carrying out of the process for the choppingof a body consisting of explosives has a chopping bench, on which a bodyof composite rocket fuel is secured, the securing means varying,depending on the size of the body of composite rocket fuel to be dividedinto portions, a nozzle fastened to a nozzle holder for a high-pressurewater jet, and at least one means for producing a relative movement,serving as chopping advance movement, between the nozzle and the body ofcomposite rocket fuel. The device is developed in such a manner that adividing of the body of composite rocket fuel into smaller parts can beeffected by the high-pressure water jet in different perpendicular,horizontal, inclined or curved surfaces.

In a preferred embodiment, the body is fixed in position on the choppingbench, that is, either clamped by a fastening device in the case of asmaller body or resting on the chopping bench in the case of largerbody, and the nozzle holder is movable, it being displaceable orswingable or displaceable and swingable.

In another preferred embodiment, the components of the device carryingout the chopping advance movements as well as the variables influencingthe parameters of the high-pressure water jet can be remotelycontrolled.

If abrasives are added to the high-pressure water jet in order toincrease the speed of chopping, water then serving as carrier for theabrasives, a nozzle of wear-resistant material is preferably used inorder to increase its life.

Further advantages and features of the invention will now be describedon the basis of two embodiments, with reference to the drawings, inwhich like reference numerals designate the same elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a) is a side view, with the body, which is to be chopped, clampedon the chopping bench and having a nozzle holder, which is arrangeddisplaceable on a frame;

FIG. 1b) is a top view of the arrangement shown in FIG. 1a);

FIG. 2a) is an end side view of a body of composite rocket fuel mountedon drive rollers, with the nozzle arranged stationary;

FIG. 2b) is a longitudinal side view of the arrangement of thearrangement of FIG. 2a).

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1a) is a side view of a chopping bench 5 with a body 1 of compositerocket fuel clamped thereon by means of clamping straps 3, the body 1being a relatively small mass of fuel. On the chopping bench 5, on eachlongitudinal side, there is arranged a guide frame 13, over which thereextends a beam 15, on which the nozzle holder 6 having the nozzle 7 forthe high-pressure water jet 2 is displaceably arranged, the beam 15being displaceable in the longitudinal direction of the body 1 ofcomposite rocket fuel. The beam 15 for the fastening of the displaceablenozzle holder 6 for the nozzle 7 is shown in FIG. 1b). Due to the factthat the nozzle holder 6 is displaceable by a first drive device which,for example, is a stepping motor controlled by an associated controlmeans, both on the beam in transverse direction to the guide frame 13and also together with the beam in longitudinal direction on the guideframe 13 by a second drive device, cuts can be made both in thetransverse direction of the body 1 of composite rocket fuel and in itslongitudinal direction parallel to the lengthwise axis, or, bysimultaneous movement of the nozzle holder 6 on the beam 15 and on theguide frame 13, in oblique surfaces. In this way, a division intoportions of the monolithic body 1 of composite rocket fuel into units ofany desired size can be effected.

In a simplified embodiment, it is, however, also possible to dispensewith separate drives for the beam in longitudinal direction of the body1 of composite rocket fuel and to carry out cuttings with thehigh-pressure water jet 2 only perpendicular to the longitudinal axis ofthe fuel.

When relatively long cylindrical bodies 1 of composite rocket fuel areconcerned, it is necessary to provide several clamping straps 3, spacedfrom each other in the lengthwise direction of the body 1, and to securethem to the chopping bench 5.

FIG. 2a) shows a side end view of a body 8 of a composite rocket fuel oflarger mass which is mounted, at its lower region, on two rollersextending in lengthwise direction, which are driven by a second drivedevice 9, the body 8 being contained in a casing which preferablyconsists of metal and extends over the length of the body 8. By thesecond drive device 9, the body 8 having the metal casing 10 is placedin rotation around its longitudinal axis. The nozzle holder 6 having anozzle 7 for the high-pressure water jet 2 is so arranged on a frame 14fastened to the chopping bench 5 that the jet of water strikes a regionof the end 11 of the body 8 in accordance with FIG. 2b), which ispresent in ring form between the inside of the metal casing 10 and theoutside of the body 8 of composite rocket fuel. By the fixing of thestationary nozzle 6 on the frame 14 of the chopping bench 5, the body 8can be scooped out of the metal casing 10 by the high-pressure water jet2 and thus be fed to a later division into portions in suitable manner.In the region between the outer cylindrical surface of the body 8 andthe inner surface of the metal casing 10 there is a binder, so that uponthe directing of the high-pressure water jet 2 into the intermediateregion 12 formed by the binder, neither the metal casing 10 nor thecomposite rocket fuel 1 is cut.

In order, if necessary, to prevent a mixing of the composite rocket fuelwith particles of metal from the metal casing 10 upon the chopping, theseparating of the casing 10 without cutting the composite rocket fuel 1is possible by a tangentially effected longitudinal cut.

By such a process and such an apparatus in accordance with theinvention, it is possible to decompose or divide into portions differentsizes of bodies 1 of composite rocket fuel with or without metal casing10 and feed them to further disposal, for example, by burning inportions, in which case the cutting energy introduced with thehigh-pressure water jet 2 is led away, so that the danger of unintendedigniting of the rocket fuel can be eliminated or greatly reduced.Furthermore, the device for the carrying out of the process of theinvention can be remote controlled and the process itself can be usedunder conditions of normal ambient pressure in order to produce dividedpieces of the composite rocket fuel of any desired size.

We claim:
 1. A process for the chopping of a body of solid explosiveinto discrete sectional portions, comprising the steps of:directing ahigh-pressure water jet emerging from a nozzle onto the body of solidexplosive; moving the nozzle and the body of solid explosive relative toeach other during the step of directing; and continuing said steps ofdirecting and moving until at least one discrete sectional portion iscut from a remaining sectional portion of the body of solid explosive.2. The process of claim 1, wherein the body of solid explosive consistsof composite rocket fuel.
 3. The process of claim 1 or 2, wherein thehigh-pressure water jet contains abrasive particles.
 4. The process ofclaim 2, wherein the nozzle is stationary and the body of compositerocket fuel carries out a chopping advance movement.
 5. The process ofclaim 4, wherein the body of composite rocket fuel is in a metal casing,a binder being disposed between the metal casing and the body ofcomposite rocket fuel, the process further comprising:rotating the bodyof composite rocket fuel with the metal casing and the binder around alongitudinal axis thereof; and at the same time longitudinally directingthe high-pressure water jet into a space containing the binder to cutthe binder in order to scoop the body out of the metal casing in a solidform.
 6. The process of any of claims 1, 2, 4, or 5, wherein choppingadvance movements of the nozzle and/or of the body of composite rocketfuel as well as operating parameters of the high-pressure water jet areremote-controlled.
 7. The process of claim 2, wherein the body ofcomposite rocket fuel is stationary and the nozzle carries out achopping advance movement.
 8. The process of claim 4 or 7, wherein thechopping advance movement is carried out around at least two axes. 9.The process of any of claims 1, 2, 4 or 7, wherein the high-pressurewater jet emerges from the nozzle with a pressure with the range of 30to 120 MPa.
 10. A process for the dividing into discrete sectionalizedportions a body of solid explosive in which a high-pressure water jetemerging from a nozzle is directed onto the body of solid explosive, andthe nozzle and the body of solid explosive carry out a movement relativeto each other during the division into portions, wherein the body isdivided up into the discrete sectionalized portions under ambientconditions without danger of ignition.
 11. The process of claim 10,wherein the body of solid explosive is in a casing which is rotatedaround a longitudinal axis and at the same time the high-pressure waterjet is directed in a ring shape between an inner side of the casing andan outer side of the body of solid explosive in order to scoop the bodyof solid explosive out of the casing.
 12. The process of claim 10 or 11,wherein the high-pressure water jet contains abrasive particles.
 13. Theprocess of claim 10 or 11, wherein at least one of the nozzle and thebody of solid explosive carries out a chopping advance movement aroundat least two axes.
 14. The process of claim 13, wherein the choppingadvance movement of the at least one of the nozzle and the body of solidexplosive as well as the parameters of the high-pressure water jet areremote controlled.
 15. The process of claim 10 or 11, wherein thehigh-pressure water jet emerges from the nozzle with a pressure withinthe range of 30 to 120 MPa.